What is the purpose of the catalyst?
a. to start the chemical reaction
b. to stop the chemical reaction
c. to speed up the chemical reaction
d. to make the chemical reaction safe to observe

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?

Calculate the molarity of each of the following solutions. part a) 0.12 mol of lino3 in 5.5 l of solution part b) 60.7 g c2h6o in 2.48 l of solution part c) 14.2 mg ki in 100 ml of solution